Development of a test method to evaluate laceration risk of studded footwear

Studded footwear has previously caused a number of severe laceration injuries in rugby union. Current test methods for assessing the laceration injury risk of rugby stud designs are unrepresentative of the game and are not mandatory for manufacturers to follow. The aim of this project was to develop a new, game-representative test method to assess the laceration injury risk of stud designs used in rugby union. First, the prevalence of skin and laceration injuries in rugby union was assessed through a systematic literature review of epidemiological studies. It was found that 2.4 skin injuries occurred per 1000 match hours, which could be interpreted as one time-loss injury per team, per season. A survey study of 191 rugby players was then conducted, indicating that stamping in the ruck was the most prevalent cause of stud laceration injuries. Following this, twelve participants were asked to perform stamping impacts in a simulated rucking scenario. Three-dimensional shoe kinematics and individual stud kinetics were measured for each impact. Two key phases were identified: an initial impact phase, and a subsequent raking phase. A two-phase mechanical test method was developed based on the results of the stamping study. In the initial impact phase, the stud is attached to a pendulum impacting a skin simulant. The velocity, stud angle and mass of the impact can be adjusted. The stud and skin simulant are then moved to the second phase, performing a controlled rake. In this phase, raking speed, stud angle and stud mass can be changed. Finally, six studs were compared on their predicted laceration injury risk using the developed method. Four of the tested studs were bespoke designs incorporating different edge radii and top diameters. The developed test method showed an increased laceration injury risk when stud edge radius or top diameter was reduced. Two of the tested studs were commercially available designs which had previously passed rugby union's current studded footwear tests. One of commercial studs showed an increased risk of laceration in the developed test method. Future research should focus on improving the developed test method's validity and investigating the influence of stud material, shape and wear on laceration injury risk.